Are you in a region that requires egress doors to unlock on an AC loss?  Typically, this is accomplished by simply not placing a backup battery set on your 24V lock power supply and using fail-safe locks.

But what if you have other locks or 24V devices you want to remain powered during an AC loss?  What if you are using fail-secure locks that need to unlock on a loss of AC power?  LifeSafety Power has a more elegant solution that offers more flexibility.

By simply integrating the AC fault relay into the FAI input circuit of the FPO power supply, you now have full control over what happens during an AC power failure using standard FAI-capable outputs.  This includes selecting which doors unlock and which don't for both fail-safe and fail-secure locks.  It also allows you to select outputs to remain powered during an AC loss.

For wiring diagrams and more information on this, see our Application Note AN-28.  And as always, our Technical Support department is here to help.

Earth Ground Fault Detection was developed for the Fire Alarm industry to give enhanced fault detection on NAC loops.  Although Earth Ground Fault Detection is not currently required in access control applications, it can still be a useful feature - provided your system is compatible.

What is Earth Ground Fault Detection?

Despite what its name might imply, Earth Ground Fault Detection does not detect a missing earth ground connection to your power supply.  Instead, it detects a connection between earth ground and any positive or negative output circuit in the system.  This includes any part of the system that is common grounded with the power supply.  If the power supply with earth ground detection is powering an access control panel, any earth ground faults on the access panel circuits (readers, etc) will show on the power supply.  If your access control panel is then common grounded with your 24VDC CCTV system's DVR, any faults on the CCTV system would also show on your power supply.  Because of this, it is important to be aware of what is connected to your system - especially when troubleshooting.

How Does Earth Ground Detection Help?

An earth ground fault does not mean you necessarily have an immediate problem.  It is simply a warning that one leg of a circuit somewhere is either partially or fully shorted to earth ground.  Usually, a single short to earth ground causes no problem in the operation of the system.  However, a second short to earth ground - even on a completely unrelated circuit, can cause a direct short circuit, leading to blown fuses, erratic operation, or even a fire.

When should I not enable Earth Ground Fault Detection?

Earth Ground Fault Detection should only be enabled on one piece of equipment within the system.  In access control, this is usually the power supply.  If the access system is common grounded with the fire system, the FACP may already have earth ground detection enabled.  Also, if there are multiple power supplies connected to the access system, only one of these supplies should have Earth Ground Fault Detection enabled - this includes two supplies within the same enclosure.

In many access control applications, even if you follow all of the rules and none of your wiring or load devices is shorted to earth ground, you may still show an Earth Ground Fault.  This is usually caused by access control panels that don't "play nice" with earth ground fault detection.  As stated above, Earth Ground Fault Detection is not a requirement in access control.  Many access panels require shielded communications circuits and the panel manufacturers connect these shields to earth ground and DC ground for better shielding or other RF noise or transient requirements.  In these cases, the only option is to disable the Earth Ground Fault Detection entirely.

Troubleshooting Earth Ground Faults

For more information, our application note AN-32 (Troubleshooting Earth Ground Faults) goes in-depth on how earth ground fault detection works and the best method of troubleshooting earth ground fault conditions.  And as always, our Technical Support Department is always here to help.

At first glance our Fire Alarm Input (FAI) may seem a bit more complicated than the competition's, but when you know why and how it helps you in the field, it will quickly become your new best friend.

Traditionally, FAI inputs have been dry contact input only, and typically only accepted a NO contact or a NC contact, depending on the manufacturer or product.  There was no ability to change the type of input - if you had a NO-type FAI input and a NC contact from the fire panel, you had two choices:  call the fire panel installer to switch it to NO or install a relay between the FACP and the FAI input.

LifeSafety Power has you covered! The FAI input on the FPO power supply line is configurable for virtually any type of input out of the box.  It will accept a NO or NC dry contact, voltage input, open collector (transistor) input, or even a polarity reversal on a fire alarm NAC loop.  The key to its flexibility is in its wiring, which necessitates extra terminals in comparison to a traditional FAI input.

The FAI input of the FPO power supply has six terminals, which can be divided into pairs:

I+ and I- terminals are the actual input to the FAI circuit.  They are opto-isolated, accept a voltage from 9-30VDC, and are polarized to ignore a reverse polarity voltage as you would see in the standby state of a NAC loop.

V+ and V- supply an auxiliary voltage which can be used in conjunction with dry contacts or other methods for activating the I+ and I- terminals.  This voltage is current limited and if it shorts will only allow 10-15mA of current to pass.  This not only protects the activation contact, it allows this voltage to be shunted in the NC dry contact application.  If the V+ is connected to I+ and V- is connected to I-, the FAI input will activate (shown by the illumination of the red FAI LED on the FPO power supply).

The two L terminals allow latching of the FAI input.  This is required in some regions including areas of Canada.

Our application note AN-27 General FAI Usage can be used along with the FPO Power Supply instruction manual and PowerPro TV FAI Training Video to gain even more knowledge on the FAI input.  And as always, our This e-mail address is being protected from spambots. You need JavaScript enabled to view it team is always here to help.

Building or decoding a model number for a FlexPower system can be intimidating at first, but once you understand the components of the model number, you will be building customized model numbers in no time. 

Building an FPO Model Number

To start this discussion, we will use the following example model number:

FPO75/150-C82D8PNL2E4M1

FlexPower model numbers are broken into two sections.  Every FlexPower model number starts with the main power source(s) - in the above example, this would be the "FPO75/150".  This denotes a dual voltage system using an FPO75 and an FPO150 for the power sources.  In a single voltage system using an FPO150, this would be simply "FPO150" without the slash.  Up to three FPO power supplies may be configured into one model number (FPO75/150/150).  FPO power supplies are always represented in the model number in order from smallest to largest.

After the hyphen are any accessory boards and the enclosure size.  In the example model number above, there are a total of four accessory boards.  A C8 board, two D8P boards, and an NL2 board.  Accessory boards are always listed in alphanumeric order (i.e. B100 before C4, C4 before C8, C8 before M8, etc.).  Quantities are added to the accessory board only when the quantity is greater than 1.  So the single NL2 is shown simply as "NL2" while the two D8P boards are shown as "2D8P".

The enclosure size comes at the end of the model number and is shown as E___.  In the example above, the E4M1 M-Class enclosure is being used.

Building an FPA Model Number

FPA150A-2A8E1

This model number breaks down to an FPA150A AC power source, two A8 fused distribution boards, and an E1 enclosure.  Multiple FPA300A power sources can be combined in the model number to become FPA600A or FPA900A.

Building an FPX Model Number

FPX300A/75/150-A8C82D8E4

The FPX system combines AC and DC power in a single enclosure.  The AC power source(s) are always listed first in an FPX model number, followed by the FPO power source(s).  AC Power sources in the model number are appended with an "A", so a "150A" is an FPA150A and a "150" is an FPO150.  This example includes the FPA300A AC source, an FPO75, and an FPO150.  It has a single A8 AC distribution board, a C8 lock control board, and two D8 auxiliary output boards.  This is all housed in an E4 enclosure.

Those are the basics of building FPO, FPA, or FPX model numbers.  A visual guide to building model numbers is also available HERE.  And remember - if this is all still a little too much to take in, our This e-mail address is being protected from spambots. You need JavaScript enabled to view it is always here to help you build any model number you may need.

Smarter Power Solutions courtesy LifeSafetyPower

At LifeSafety Power, we're committed to helping the industry make better educated decisions about power for access control, security, fire systems, mass notification and CCTV systems.  So we're launching this blog site - with the goal of engaging and educating readers on the latest innovation in power solutions.

Some of the planned topics include new product announcements; insights and technical information on specifications; the company, our leaders and our expertise; and frequently asked questions or need-to-know tidbits.

Watch for the launch, and follow us on Twitter and like us on Facebook to find out more.